Liquid crystal display devices, due the advantages of high definition, small size, light weight, low driving voltage, low power consumption, and the like, have been widely used in various IT digital products, such as automobile guidance systems, engineering workstations, monitors, portable information terminals, electronic terminals, electronic books, notebook computers, and large-scale direct view flat-panel televisions.
As one of the most important components of a liquid crystal display device, a liquid crystal display substrate can be manufactured through three stages including an array procedure, a cell procedure, and a module procedure, wherein the array procedure is performed to form a TFT loop on a glass substrate, and further includes washing, film forming, photoetching, and examining steps, among others.
ICP etching, which is widely used among existing LTPS procedures, includes rather complex chemical and physical steps. The chemical steps substantially comprise two portions: one portion is glow discharge of an etching gas through inductive coupling, to produce active free radicals, metastable particles, atoms, and chemical interactions thereamong; and the other portion involves interactions between these active particles generated in the glow discharge of the etching gas and a surface of the substrate. The physical steps mainly include bombardment against the surface of the substrate by ions.
ICP etching has the advantages of anisotropy, high etching rates, controllable procedures, and the like. However, due to a comparatively large power density, ICP etching would cause GI-SIOx losses in practical manufacturing procedures, thereby deteriorating homogeneity of the substrate.